AIM: To investigate the effects of autotransfusion on immune function and inflammation in patients undergoing cesarean section. METHODS: Ninty patients with high risk hemorrhage (central placenta previa, cicatritic uterus, etc.) who underwent cesarean section were divided into three groups according to the amount of autoblood transfusion, with 30 cases in each group. The control group did not receive autologous blood transfusion, the group with a transfusion volume of 0-400 mL received autologous blood transfusion 0-400 mL, and the group with a transfusion volume of 400-800 mL received autologous blood transfusion 400-800 mL. Serum levels of HB, RBC, HCT, WBC, CD3+, CD4+ and CD8+ were detected before surgery (T0), immediately after surgery (T1), 24 h after surgery (T2), 48 h after surgery (T3), CD4+/CD8+ ratio was calculated, and serum levels of IL-2 and IL-6 were measured. The mean arterial pressure, heart rate, oxygen saturation, postoperative fever and length of stay were recorded. RESULTS: Compared with T0, the changes of CD3+, CD8+, CD4+/CD8+ ratio, IL-2 level, mean arterial pressure, heart rate and oxygen saturation were similar among the three groups at each time point after surgery (P>0.05). CD4+ in the 0-400 mL reinfusion group and the 400-800 mL reinfusion group was higher than that in T0 at T2 (P<0.05), and IL-6 and WBC in the three groups were higher than that in T0 at all time points after surgery (P<0.05). The levels of HB, RBC and HCT in the control group decreased at T1, while the levels of HB, RBC and HCT in the 0-400 mL and 400-800 mL reinfusion groups decreased at T2 (P<0.05). Comparison between groups: at the same time point after surgery, the ratio of CD3+, CD8+, CD4+/CD8+, IL-2, IL-6, HB, RBC, HCT, WBC, mean arterial pressure, heart rate, oxygen saturation, postoperative fever, length of hospital stay and other changes were similar among the three groups (P>0.05). CD4+ concentration in 0-400 mL reinfusion group and 400-800 mL reinfusion group was higher at T2 than that in control group (P<0.05). CONCLUSION: Autologous blood transfusion can not inhibit immune function, and even improve immune function in the short term. It will not aggravate the inflammatory response of the body, so it is safe and available.